CN109608701A

CN109608701A - A kind of thermoplastic starch based foam material and preparation method

Info

Publication number: CN109608701A
Application number: CN201811496069.2A
Authority: CN
Inventors: 陈勋森; 叶正涛
Original assignee: SHANGHAI NYTEX COMPOSITES PRODUCT CO Ltd
Current assignee: SHANGHAI NYTEX COMPOSITES PRODUCT CO Ltd
Priority date: 2018-12-07
Filing date: 2018-12-07
Publication date: 2019-04-12

Abstract

The invention discloses a kind of thermoplastic starch based foam material and preparation methods.Include the following steps: that starch, plasticiser and preplasticizing dispersant are 1. obtained starch mixed liquor I；2. resistance to water reaction agent, reinforcing agent are mixed to obtain starch mixed liquor I I with starch mixed liquor I；3. starch gel compound is made in starch mixed liquor I I hybrid reaction in treatment with supercritical fluid system；4. being continually fed into supercritical fluid into starch gel compound in treatment with supercritical fluid system, decompression is cooling to obtain the final product.The present invention modifying agent can be added during starch gelization and reinforcing agent carries out a step modified-reaction, can be prepared by water-resistant type starch based foam material by traditional thermoplastic fabrication equipment, preparation method is simple under conditions of supercritical carbon dioxide；The expansion ratio of gained starch based foam material is high, and cell density is low, incompressible intensity retention rate with higher and preferable water resistance in long-time placement process.

Description

A kind of thermoplastic starch based foam material and preparation method

Technical field

The present invention relates to a kind of thermoplastic starch based foam material and preparation methods.

Background technique

Foamed plastic refers to using polymer such as plastics, rubber, elastomer or natural macromolecular materials as matrix, a large amount of bubbles (cell diameter is less than 10 μm and cell density is greater than 1 × 10⁸cell/cm³) it is scattered in product formed in solid polymer, It is widely used as adsorbent, insulation, packet with good toughness, endurance, heat-resisting, low-k and electric conductivity Dress, biomedical and light overpressure resistant anti-seismic material etc..However, such as polyphenyl second of polymer used in most of foaming plastics products Alkene, polyolefin and polyurethane etc. are petroleum-based plastics, are often used chemical foaming agent or electricity again during practical foam application Beamlet reinforces foaming, these can bring huge environmental pollution and the energy to continue exhaustion.

To solve foregoing problems, production academics carries out foamed material preparation with Biodegradable material in recent years, on solving State the doubt in common petroleum base expanded plastic material use.And then mainly exist to the research of biodegradable foamed material at present Foaming aspect is blended in the degradable polymers such as polylactic acid (PLA), starch and polylactic acid, polyhydroxyalkanoates.Such as Chinese patent Document CN1923890A is disclosed using poly- (3-hydroxybutyrate ester-co-4- butyric ester) (P3HB4HB), PLA and foaming agent Manufacture foamed material is blended；Equally, Chinese patent literature CN101245175A is also disclosed with PLA, polyhydroxyalkanoates copolymerization Object and cornstarch etc. are the foamed material of primary raw material preparation, but intensity due to above-mentioned foaming product and expansion ratio are not Height, hygroscopic, therefore it is limited in use.Existing disclosed patent US5348983, US5378792, US5422053, The preparation method of polylactic acid foam material is disclosed in CN101151310B and CN1810877B etc.；CN1919926B, The preparation method of PLA/ starch blending foamed material is disclosed in CN101386703B and CN107841099A etc..Although PLA is Renewable and biodegradable material, but PLA degradation will carry out under composting conditions, and degradation condition is harsher, for people The degradation of the PLA foamed material arbitrarily abandoned relatively slowly even is difficult to degrade, thus still not can solve increasingly serious white Color pollution problem.Along with the expansion ratio of PLA class A foam A material is lower, expensive, industrial production is at high cost, embarrasses industry It is widely used.

Source is most abundant in nature, inexpensive, and readily biodegradable recyclable materials then first elect starch and plant is fine Dimension, in recent years as the important research of production academics's foamed material and using raw material.Currently, though several researchs are to inexpensive and renewable Starch is esterified, acetylation, etherificate and crosslinking or be blended Biodegradable polymer material (such as plant fiber, polylactic acid and Chitosan etc.) improve pure starch foaming product strength and water resistance property, but the hair of the pure starch base product of conventional method preparation The intensity and water-proofing performance for steeping multiplying power still relatively low (≤10 times) and product are still slightly inadequate.Chinese patent literature CN107936437A It discloses and modified corn starch based foam material is made using die pressing, although having preferable tensile strength, impact strength And elongation at break, but its expansion ratio is lower, and moisture resistance properties are also that its another major defect will be such that it is not suitable for for a long time Loading uses.

Supercritical fluid (Supercritical fluids, SCF) be substance be in its critical-temperature and pressure or more and A kind of special state fluid formed.This fluid has both the property of gas and liquid, such as diffusion coefficient, and density is big, and viscosity is low, Have good heat transfer and mass transfer characteristic, the physical parameters such as Near The Critical Point its density, dielectric constant and solubility property to temperature and Pressure is especially sensitive.The substance for being commonly used for SCF has CO₂、H₂O、CH₄、CH₃OH、C₂H₅OH and NH₃Deng the SCF of most common of them is Supercritical carbon dioxide fluid (Supercritical carbon dioxide fluid, scCO₂F), because of its CO₂It is from a wealth of sources, It is not easy to blast with lower critical-temperature and pressure, it is cheap, convenient for recycling.Because of scCO₂F solvability is adjustable, right High polymer has very strong dissolution swelling and diffusivity, has many advantages, such as good plastication, product easy purification, and answers extensively Production etc. for foamed material.

Chinese patent literature CN104419018A discloses a kind of composite foamed material of modified starch (esterification or etherification starch) Prepared modified starch pellet is entered overcritical or close supercritical foaming through the rectangular test piece of ejection formation by the preparation method of material Processing procedure is made the foam sample that expansion ratio is 14.9, but still has the defect of poor moisture resistance.Chinese patent literature CN105461967A discloses one kind by thermoplastic starch, nanoplant fiber, starch-polylactic acid graft copolymer and aeroge Powder etc. is combined, and passes through scCO₂The lightweight starch base high tenacity composite foam material that " extrusion foaming " is process, according to Its expansion ratio of abscess-size (150-250 μm) deducibility is relatively low (≤15 times), and need to be with the poly- cream of other biological degraded macromolecular Sour graft copolymer and aerogel powder auxiliary foaming.Although in addition, above-mentioned foamed material all with several expansion ratio and Good initial elastic and starting damping characteristics, but more complex (the extrusion foaming non-scCO of preparation process₂Condition), and moisture-proof Difference is being stored and is often being gone mouldy in application process because absorbing in environment caused by moisture so as to cause the substantially drop of every mechanical property It is low.The patent of Publication No. CN105461970A uses hydroxypropul starch, starch-grafted glycidyl methacrylate, starch G-polycaprolactone, polycaprolactone, chitosan, waterproofing agent and antioxidant are combined into a kind of biomass combined anti-biotic material, and lead to Cross scCO₂Foamed material is made in " extrusion foaming ", according to its expansion ratio≤15 times of abscess-size (100-200 μm) deducibility； Though above-mentioned patent is effectively improved waterproof, anti-mildew and antibiotic property, more complex (the extrusion foaming non-scCO of preparation process₂Item Part), and its finished product expansion ratio (≤15 times) is relatively low, more need to other biological degraded macromolecular (such as Starch grafted polycaprolactone, Polycaprolactone etc.) auxiliary foaming.In addition, above-mentioned antimildew and antibacterial foamed product changes because only carrying out resistance to aquation on starch surface in processing procedure Property, its mechanical strength is influenced to report after not actually attempting to long-time aging (moisture absorption) test.

Temporarily have no that expansion ratio is high, moisture resistance properties are good, strength retention ratio is high and preparation method is simple in currently available technology Pure starch based foam material.

Summary of the invention

Technical problem to be solved by the present invention lies in overcome the pure starch of prior art foaming or starch base to answer material foaming times Rate is low, poor moisture resistance or preparation process complexity defect, provides a kind of thermoplastic starch based foam material and preparation method.This Modifying agent is added during starch gel and carries out a step moisture-proof and foaming modification for invention, and preparation method is simple, shallow lake obtained Powder based foam material expansion ratio is high, initial incompressible intensity and has preferable moisture-proof and resistance to compression in long-term placement process Contracting strength retention ratio is high.

The present inventor has found that the foam sample prepared will appear in placement process by lot of experiments The problem of obvious abscess collapses, inventor's discovery by freeze-drying or do the foam sample just prepared It is dry to keep abscess pattern, but effect is bad.It has furthermore been found that during preparing foam, in a high pressure reaction kettle Intake valve and air outlet valve are opened, supercritical fluid is continually fed into, a large amount of water can not only be taken away by the circulation of supercritical fluid Point, achieve the effect that dried foam sample, while abscess pattern can also be kept, so as not to collapse (test condition: 20 DEG C/50% relative humidities under place 48 hours after observable its volume change).

The present invention solves above-mentioned technical problem by the following technical programs.

The present invention provides a kind of preparation methods of thermoplastic starch based foam material comprising following step:

(1) in mass ratio it is 1:(0.2-0.4 by starch, plasticiser and preplasticizing dispersing agent): (0.2-1.2) mixing is equal It is even, obtain starch mixed liquor I；The additive amount of the starch is 40-50g/L, and the additive amount of above-mentioned starch is the quality of the starch With in treatment with supercritical fluid system described in step (3) reaction kettle volume the ratio between；

(2) resistance to water reaction agent, reinforcing agent are uniformly mixed with the starch mixed liquor I, obtain starch mixed liquor I I；

(3) in treatment with supercritical fluid system, starch mixed liquor I I hybrid reaction described in step (2) is made and is formed sediment Powder gel compound；Wherein, the temperature of the hybrid reaction is 70-120 DEG C, and the time of the hybrid reaction is 10-40 minutes；Institute State starch mixed liquor I I inventory be less than 130g/L, above-mentioned inventory be the starch mixed liquor I I quality and it is described surpass face In boundary's fluid handling system reaction kettle volume the ratio between；

(4) in treatment with supercritical fluid system, supercritical fluid is continually fed into the starch gel compound, it It depressurizes afterwards, is cooling to get thermoplastic starch based foam material.

In step (1), the starch is routine in the art, is better selected from native starch and/or is modified by starch The modified starch of agent.The native starch is routine in the art, is better selected from cornstarch, wheaten starch, sweet potato and forms sediment One of powder, potato starch and tapioca are a variety of, are more preferably tapioca.The starch dressing agent is ability It is conventional in domain, it is better selected from one of carboxylic acid, acid anhydrides, carboxylic acid halides and amide or a variety of.Wherein, the carboxylic acid is preferably One of citric acid, acetic acid, malic acid and sebacic acid are a variety of；The acid anhydrides is preferably acetic anhydride and/or maleic acid Acid anhydride；The carboxylic acid halides is preferably acyl chlorides；The amide is preferably formamide, N-METHYLFORMAMIDE and dimethyl acetamide One of or it is a variety of.

In step (1), the mixing, which is preferably placed in machine mixer, cuts dispersion mixing, more preferably in machinery Dispersion mixing 0.5-1 hours is cut in blender, most preferably to cut dispersion mixing 1 hour in machine mixer.

In step (1), the plasticiser generally refers to prepare thermoplastic starch-based foam material field conventional use of One of plasticiser, preferably ethylene glycol, glycerine, dimethyl sulfoxide and urea are a variety of, are more preferably glycerine.

In step (1), the preplasticizing dispersing agent is usually that one kind makes starch and plasticiser under certain condition can be with It is uniformly mixed the liquid reagent of dispersion, preferably one of ethyl alcohol, water and methanol or a variety of, is more preferably water.

In step (1), in starch mixed liquor I, the quality of the starch, the plasticiser and the preplasticizing dispersing agent Than being preferably 1:(0.2-0.4): (0.6-1) is more preferably 1:(0.2-0.4): (0.6-0.8), such as 1:0.4:0.6.

In step (1), if the additive amount of the starch is less than 40g/L, starch additive amount is very few, and gained foam is easy to collapse It falls into；If the additive amount of the starch is greater than 50g/L, starch additive amount is excessive, and gained foam sample density becomes larger.

In step (2), the resistance to water reaction agent refers under certain condition, can chemically react with starch, make starch Molecular surface hydrophilic group is reduced, and increases the chemical reaction reagent of starch water resistance, is better selected from more aldehydes, amides, is gathered One of vinyl alcohol and organic acid anhydride are a variety of, are more preferably more aldehydes.The amides are preferably formamide.

Wherein, when the resistance to water reaction agent is more aldehydes, the mass ratio of the resistance to water reaction agent and the starch Preferably (0-3.2): 100, be more preferably (0.2-1.6): 100, be most preferably (0.4-1.6): 100, such as (0.8- 1.6):100.When the resistance to water reaction agent is no esters, the mass ratio of the resistance to water reaction agent and the starch is preferable Ground is (0-32): 100.When the resistance to water reaction agent is amides, the quality of the resistance to water reaction agent and the starch Than preferably (0-5): 100, be more preferably (1.25-5): 100, such as 1.6:100.When the resistance to water reaction agent is polyethylene When alcohol, the mass ratio of the resistance to water reaction agent and the starch is preferably (0-10): 100, such as 1.6:100,2:100 Or 2.5:100.When the resistance to water reaction agent is organic acid anhydride, the quality of the resistance to water reaction agent and the starch Than preferably (0-3): 100.

Wherein, more aldehydes can be the resistance to water reaction agent of more aldehydes for being dissolved in water of this field routine, preferably second two One of aldehyde, butanedial and glutaraldehyde are a variety of.The amides can be the conventional resistance to water reaction agent of amides in the art, Preferably formamide and/or acetamide.The organic acid anhydride can be water-fast for conventional organic acid anhydride in the art One of reactant, preferably citric acid, succinic acid, maleic anhydride and ortho-xylene acid anhydrides are a variety of.

In step (2), the resistance to water reaction agent preferably exists in form of an aqueous solutions, in the aqueous solution of resistance to water reaction agent In, the mass percent of resistance to water reaction agent is preferably 20-40%, is more preferably 25%.

In step (2), the reinforcing agent be Biodegradable polymer material, generally plant fiber, nano-cellulose, One of bacteria cellulose, polylactic acid, chitosan and polyesteramide are a variety of, preferably plant fiber, nano-cellulose It is more preferably nano-cellulose with one of bacteria cellulose or a variety of.The plant fiber is preferably cellucotton.

Wherein, when reinforcing agent is plant cellulose, the mass ratio of the reinforcing agent and the starch is preferably (0.01-0.04): 100, it is more preferably 0.02:100.When reinforcing agent is nano-cellulose, the reinforcing agent and the starch Mass ratio be preferably (0.01-0.04): 100, be more preferably 0.02:100.It is described when reinforcing agent is bacteria cellulose The mass ratio of reinforcing agent and the starch is preferably (0.01-0.08): 100.When reinforcing agent be chitosan, the reinforcing agent and The mass ratio of the starch is preferably 0.1:100.

In step (2), the specific surface area of the reinforcing agent is preferably 100-150m²/ g is more preferably 120m²/g.It is described The diameter of reinforcing agent is preferably 10-30nm, is more preferably 20nm.

In step (3), the supercritical fluid refer to that substance is in its critical-temperature and pressure or more and formed one Kind special state fluid.This fluid has both the property of gas and liquid, such as viscosity, density, diffusion coefficient, solvability Property changes very sensitive with temperature and pressure.Viscosity and diffusion coefficient are close to gas, and density and solvability are close to liquid Body.Substance as supercritical fluid can routinely can be used as the substance of supercritical fluid, preferably CO for chemical field₂、H₂O、 CH₄、CH₃OH、C₂H₅OH or NH₃, it is more preferably CO₂。

In step (3), the hybrid reaction generally carries out in a high pressure reaction kettle.The temperature of the hybrid reaction compared with It is goodly 70-100 DEG C, is more preferably 85 DEG C.The time of the hybrid reaction is preferably 15-25 minutes, is more preferably 20 Minute.

In step (3), starch mixed liquor I I described in step (2) is placed in the treatment with supercritical fluid system Operation can be conventional for this field, preferably carries out in the steps below: starch mixed liquor I I described in step (2) is placed in high pressure In reaction kettle, at 15-25 DEG C (if temperature is excessively high, sample part can be made to be gelatinized too early, influence experimental result, if temperature is too low, Will increase the reaction time, waste of resource increases processing cost) supercritical fluid is pressurized to 7-25MPa with booster pump.? The expansion ratio of sample is made in this pressure limit, incompressible strength retention ratio is more preferably.Pressure in the autoclave compared with It goodly is 7-20MPa, such as 9MPa, 11MPa.

In step (3), when the hybrid reaction, stirring rate can be conventional for this field, and preferably 100-300 revs/min Clock is more preferably 190 revs/min.

In step (3), the inventory of the starch mixed liquor I I need to be less than 130g/L, when if more than 130g/L, due to throwing Material is excessive to fill up foam sample by the mold of reaction kettle, its sample can not be made sufficiently to expand.In view of if inventory is very few So that the foam sample prepared every time is very little, it is unfavorable for the test angle of experiment, the inventory of the starch mixed liquor I I is preferable Ground is 80g/L-130g/L, is more preferably 100g/L.

Described when being continually fed into the supercritical fluid in step (4), gas flow rate can be conventional for this field, preferably It is more preferably 80 ml/mins for 50-150 ml/min.Being passed through the supercritical fluid time is preferably 1-3 hours, more preferably Ground is 2 hours.

In step (4), the operation of the decompression can be conventional for this field, and system pressure is generally decompressed to normal pressure, The system pressure is standard atmospheric pressure.

In step (4), the operation of the cooling can be conventional for this field, generally by system cooled to room temperature.It is described Room temperature refers generally to 0-30 DEG C, such as 20-25 DEG C.

Preferably, thermoplastic starch based foam material described in step (4) is removed the preformed agent in step (1).Institute Stating and removing the operation of the preformed agent in step (1) to be chemical field routine, preferably, the starch gel compound is carried out It is dry.When resistance to water reaction agent in form of an aqueous solutions in the presence of, while dry also can by the aqueous solution of resistance to water reaction agent into Row water removal.

Wherein, the temperature of the drying is preferably 0-100 DEG C, is more preferably 60-100 DEG C.The time of the drying compared with It is goodly 0.5-50 hours, is more preferably 2-50 hours.The operation of the drying preferably carries out in the steps below: will be described After starch gel compound is first placed in air dry oven or the drying of infrared ray direct heat drying case, places into vacuum oven or dew point is dry Dry case is dry.The moisture control of product is in≤0.5wt% after drying.

Wherein, the air dry oven or the temperature of infrared ray direct heat drying case drying are preferably 75-85 DEG C, more preferably It is 80 DEG C.Dry time preferably 5-10 hours of the air dry oven or infrared ray direct heat drying case, it is more preferably small for 8 When.The vacuum oven or the temperature of dew point drying box drying are preferably 0-100 DEG C, are more preferably 60-100 DEG C, most preferably Ground is 80 DEG C.The time of the vacuum oven or the drying of dew point drying box is preferably 4-30 hours, more preferably small for 10-30 When, it is most preferably 8 hours.

The present invention also provides one kind thermoplastic starch based foam material as made from above-mentioned preparation method.

In one embodiment of the present invention, the penta of high foamability is prepared using supercritical carbon dioxide secondary process technology Dialdehyde and modifying nanometer cellulose thermoplastic starch foamed material, when wherein glutaraldehyde content is 1.6PHR, nano-cellulose contains When amount is 0.02PHR, the expansion ratio of foam sample is 50, density of material 0.03g/cm³, it is 8 × 10 that density is steeped in hole⁸cell/ cm³, incompressible intensity is positively retained at 0.07MPa after foam sample is placed 56 days under 20 DEG C/50% relative humidities, resists Compressive strength retention rate is up to 46.7%, water absorption rate 4.0%.

On the basis of common knowledge of the art, above-mentioned each optimum condition, can any combination to get each preferable reality of the present invention Example.

The reagents and materials used in the present invention are commercially available.

The positive effect of the present invention is that:

1, modifying agent and enhancing can be added under conditions of supercritical carbon dioxide in the present invention during starch gelization Agent carries out a step modified-reaction, can be prepared by water-resistant type starch based foam material by traditional thermoplastic fabrication equipment, makes Preparation Method is simple.2, the expansion ratio of starch based foam material produced by the present invention is high, and cell density is low, places for a long time Incompressible intensity retention rate with higher and preferable water resistance in journey.

Detailed description of the invention

Fig. 1 is embodiment 1-15, and the thermoplastic starch based foam material density and expansion ratio of comparative example 1-13 is with penta 2 Aldehyde aqueous solution additive amount change curve.Wherein, ● it is comparative example 1,For comparative example 2,For comparative example 3,For comparative example 4, For comparative example 5,It is comparative example 7 for comparative example 6, zero, ■ is comparative example 8,For comparative example 9, ▲ it is comparative example 10, ▼ is comparison Example 11, △ are comparative example 12, and ▽ is comparative example 13,For embodiment 1,For embodiment 2,For embodiment 3,For embodiment 4, For embodiment 5,For embodiment 6,For embodiment 7,For embodiment 8,For embodiment 9, ★ is embodiment 10,For embodiment 11,For embodiment 12, ◇ is embodiment 13, and is embodiment 14, and ☆ is embodiment 15.

Fig. 2 is the abscess-size and cell density of the thermoplastic starch based foam material of embodiment 1-15 and comparative example 8-13 With glutaraldehyde water solution additive amount change curve.Wherein, ■ is comparative example 8,For comparative example 9, ▲ it is comparative example 10, ▼ is Comparative example 11, △ are comparative example 12, and ▽ is comparative example 13,For embodiment 1,For embodiment 2,For embodiment 3,To implement Example 4,For embodiment 5,For embodiment 6,For embodiment 7,For embodiment 8,For embodiment 9, ★ is embodiment 10,For Embodiment 11,For embodiment 12, ◇ is embodiment 13, and is embodiment 14, and ☆ is embodiment 15.

Fig. 3 is the cross-section morphology SEM photograph of the thermoplastic starch based foam material of comparative example 1-2,4-6,8-13.Wherein, (a) it is comparative example 1, (b) is comparative example 2, (c) be comparative example 4, (d) be comparative example 5, (e) be comparative example 6, (f) is comparative example 8, (g) it is comparative example 9, (k) is comparative example 10, (l) be comparative example 11, (p) be comparative example 12, (q) is comparative example 13.

Fig. 4 is the cross-section morphology SEM photograph of the thermoplastic starch based foam material of embodiment 2-4,7-9,12-14.Wherein, (h) it is embodiment 2, (i) is embodiment 3, (j) be embodiment 4, (m) be embodiment 7, (n) be embodiment 8, (o) is embodiment 9, (r) it is embodiment 12, (s) is embodiment 13, (t) is embodiment 14.

Fig. 5 is embodiment 1-15, and the melt index of the thermoplastic starch based foam material of comparative example 1-13 is with glutaraldehyde water Solution additive amount change curve.Wherein, ● it is comparative example 1,For comparative example 2,For comparative example 3,For comparative example 4,It is right Ratio 5,It is comparative example 7 for comparative example 6, zero, ■ is comparative example 8,For comparative example 9, ▲ it is comparative example 10, ▼ is comparative example 11, △ be comparative example 12, and ▽ is comparative example 13,For embodiment 1,For embodiment 2,For embodiment 3,For embodiment 4,For Embodiment 5,For embodiment 6,For embodiment 7,For embodiment 8,For embodiment 9, ★ is embodiment 10,For embodiment 11,For embodiment 12, ◇ is embodiment 13, and is embodiment 14, and ☆ is embodiment 15.

Fig. 6 is embodiment 1-15, and the thermoplastic starch based foam material of comparative example 1-13 is in 20 DEG C/50% relative humidity item Under part moisture content with standing time change curve.Wherein, ● it is comparative example 1,For comparative example 2,For comparative example 3,It is right Ratio 4,For comparative example 5,It is comparative example 7 for comparative example 6, zero, ■ is comparative example 8,For comparative example 9, ▲ it is comparative example 10, ▼ is comparative example 11, and △ is comparative example 12, and ▽ is comparative example 13,For embodiment 1,For embodiment 2,For embodiment 3,For Embodiment 4,For embodiment 5,For embodiment 6,For embodiment 7,For embodiment 8,For embodiment 9, ★ is embodiment 10,For embodiment 11,For embodiment 12, ◇ is embodiment 13, and is embodiment 14, and ☆ is embodiment 15.

Fig. 7 is the thermoplastic starch based foam material of embodiment 1-15 and comparative example 8-13 in 20 DEG C/50% relative humidity Under the conditions of initial incompressible intensity with glutaraldehyde water solution additive amount change curve.Wherein, ■ is comparative example 8,For comparison Example 9, ▲ it is comparative example 10, ▼ is comparative example 11, and △ is comparative example 12, and ▽ is comparative example 13,For embodiment 1,For embodiment 2,For embodiment 3,For embodiment 4,For embodiment 5,For embodiment 6,For embodiment 7,For embodiment 8,To implement Example 9, ★ are embodiment 10,For embodiment 11,For embodiment 12, ◇ is embodiment 13, and is embodiment 14, and ☆ is embodiment 15。

Fig. 8 is the thermoplastic starch based foam material of embodiment 1-15 and comparative example 8-13 in 20 DEG C/50% relative humidity Under the conditions of incompressible intensity with standing time change curve.Wherein, ■ is comparative example 8,For comparative example 9, ▲ it is comparative example 10, ▼ be comparative example 11, and △ is comparative example 12, and ▽ is comparative example 13,For embodiment 1,For embodiment 2,For embodiment 3, For embodiment 4,For embodiment 5,For embodiment 6,For embodiment 7,For embodiment 8,For embodiment 9, ★ is embodiment 10,For embodiment 11,For embodiment 12, ◇ is embodiment 13, and is embodiment 14, and ☆ is embodiment 15.

Specific embodiment

The present invention is further illustrated below by the mode of embodiment, but does not therefore limit the present invention to the reality It applies among a range.In the following examples, the experimental methods for specific conditions are not specified, according to conventional methods and conditions, or according to quotient The selection of product specification.

Embodiment 1

Formula rate described in following table 1 prepares thermoplastic starch based foam material.

(1) by starch (tapioca), plasticiser (glycerol) and preplasticizing dispersing agent (water) 5:2:3 in mass ratio are in machinery It is cut dispersion mixing 1 hour in blender, and nano-cellulose 0.02PHR and glutaraldehyde solution 0.2PHR is added, starch is made Mixed liquor, wherein glutaraldehyde exists in form of an aqueous solutions as hydrophobic anti-agent, mass fraction 25%, the ratio of nano-cellulose Surface area is 120m²/ g, diameter 20nm, the additive amount of starch are 50g/L；

(2) by above-mentioned (1) item mix starch mixed liquor is put into autoclave, at 25 DEG C with booster pump pressurization two Carbonoxide is to 7.0MPa, and wherein the inventory of starch mixed liquor is 100g/L；

(3) in treatment with supercritical fluid system, temperature in autoclave is risen to 85 DEG C by high/low temperature all-in-one machine, It is gelatinized 20 minutes under 190 revs/min of magnetic stirrers, obtains starch gel compound；

(4) in treatment with supercritical fluid system, it is continually fed into CO₂2 hours starch gel compounds into step (3), Gas flow rate is 80 ml/mins, and decompression makes the starch gel compound in step (3) be cooled to room temperature (25 DEG C)/normal pressure later Starch-based foam is made in (standard atmospheric pressure)；

(5) 80 DEG C are put into very after starch-based foam made from step (4) being put into 80 DEG C of infrared drying ovens dryings 8 hours Empty drying box is 8 hours dry, moisture content≤0.5wt% of starch-based foam after control is dry.

Embodiment 2

The formula rate of following table 1 prepares thermoplastic starch based foam material.

In addition to the additive amount of glutaraldehyde water solution is different, other conditions are the same as embodiment 1.

Embodiment 3

Embodiment 4

Embodiment 5

Embodiment 6

The formula rate of following table 2 prepares thermoplastic starch based foam material.

(1) by starch (tapioca), plasticiser (glycerol) and preplasticizing dispersing agent (water) 5:2:3 in mass ratio are in machinery It is cut dispersion mixing 1 hour in blender, and nano-cellulose 0.02PHR and glutaraldehyde water solution 0.2PHR is added, be made and form sediment Powder mixed liquor；Wherein glutaraldehyde exists in form of an aqueous solutions as hydrophobic anti-agent, mass fraction 25%, nano-cellulose Specific surface area is 120m²/ g, diameter 20nm, the additive amount of starch are 50g/L；

(2) by above-mentioned (1) item mix starch mixed liquor is put into autoclave, at 25 DEG C with booster pump pressurization two Carbonoxide is to 9.0MPa, and wherein the inventory of starch mixed liquor is 100g/L；

Embodiment 7

In addition to the additive amount of glutaraldehyde water solution is different, other conditions are the same as embodiment 6.

Embodiment 8

Embodiment 9

Embodiment 10

Embodiment 11

The formula rate of following table 3 prepares thermoplastic starch based foam material.

(1) by starch (tapioca), plasticiser (glycerol) and preplasticizing dispersing agent (water) 5:2:3 in mass ratio are in machinery It is cut dispersion mixing 1 hour in blender, and nano-cellulose 0.02PHR and glutaraldehyde 0.2PHR is added, starch mixing is made Liquid, wherein glutaraldehyde exists in form of an aqueous solutions as hydrophobic anti-agent, mass fraction 25%, the specific surface of nano-cellulose Product is 120m²/ g, diameter 20nm, the additive amount of starch are 50g/L；

(2) by above-mentioned (1) item mix starch mixed liquor is put into autoclave, at 25 DEG C with booster pump pressurization two Carbonoxide is to 11.0MPa, and wherein the inventory of starch mixed liquor is 100g/L；

Embodiment 12

In addition to the additive amount of glutaraldehyde water solution is different, other conditions are the same as embodiment 11.

Embodiment 13

Embodiment 14

Embodiment 15

Embodiment 16

(1) by starch (tapioca), plasticiser (glycerol) and preplasticizing dispersing agent (water) 5:2:5 in mass ratio are in machinery It is cut dispersion mixing 1 hour in blender, and cotton fiber 0.02PHR and glutaraldehyde 1.6PHR is added, starch mixed liquor is made, Middle glutaraldehyde exists in form of an aqueous solutions as hydrophobic anti-agent, mass fraction 25%, and the additive amount of starch is 50g/L；It is fine The specific surface area of dimension element is 120m²/ g, diameter 20nm；

(3) in treatment with supercritical fluid system, temperature in autoclave is risen to 100 by high/low temperature all-in-one machine DEG C, it is gelatinized 15 minutes under 190 revs/min of magnetic stirrers, obtains starch gel compound；

Embodiment 17

(1) by starch (tapioca), plasticiser (glycerol) and preplasticizing dispersing agent (water) 5:2:3 in mass ratio are in machinery It is cut dispersion mixing 1 hour in blender, and nano-cellulose 0.02PHR and polyvinyl alcohol 2.5PHR is added, it is mixed that starch is made Liquid is closed, wherein the specific surface area of nano-cellulose is 120m²/ g, diameter 20nm, the additive amount of starch are 50g/L；

(3) in treatment with supercritical fluid system, temperature in autoclave is risen to 70 DEG C by high/low temperature all-in-one machine, It is gelatinized 15 minutes under 190 revs/min of magnetic stirrers, obtains starch gel compound；

Embodiment 18

(1) by starch (cornstarch), plasticiser (glycerol) and preplasticizing dispersing agent (ethyl alcohol) 5:2:6 in mass ratio are in machine It is cut dispersion mixing 1 hour in tool blender, and nano-cellulose 0.01PHR and polyvinyl alcohol 1.6PHR is added, starch is made Mixed liquor, wherein the specific surface area of nano-cellulose is 120m²/ g, diameter 20nm, the additive amount of starch are 50g/L；

(2) by above-mentioned (1) item mix starch mixed liquor is put into autoclave, be pressurized at 25 DEG C with booster pump H₂O to 9.0MPa, wherein the inventory of starch mixed liquor is 100g/L；

(3) in treatment with supercritical fluid system, temperature in autoclave is risen to 75 DEG C by high/low temperature all-in-one machine, It is gelatinized 15 minutes under 190 revs/min of magnetic stirrers, obtains starch gel compound；

Embodiment 19

(1) by starch (wheaten starch), plasticiser (glycerol) and preplasticizing dispersing agent (ethyl alcohol) 5:2:3 in mass ratio are in machine It is cut dispersion mixing 0.5 hour in tool blender, and chitosan 0.1PHR and formamide 1.6PHR is added, starch mixing is made Liquid, the additive amount of starch are 50g/L；

(3) in treatment with supercritical fluid system, temperature in autoclave is risen to 90 DEG C by high/low temperature all-in-one machine, It is gelatinized 20 minutes under 190 revs/min of magnetic stirrers, obtains starch gel compound；

(4) in treatment with supercritical fluid system, it is continually fed into CO₂3 hours starch gel compounds into step (3), Gas flow rate is 80 ml/mins, and decompression makes the starch gel compound in step (3) be cooled to room temperature (25 DEG C)/normal pressure later Starch-based foam is made in (standard atmospheric pressure)；

Embodiment 20

(1) starch (Acid modified starch), plasticiser (ethylene glycol) and preplasticizing dispersing agent (water) 5:2:5 in mass ratio are existed It is cut dispersion mixing 0.8 hour in machine mixer, and bacteria cellulose 0.08PHR and polyvinyl alcohol 2PHR is added, be made and form sediment Powder mixed liquor, the additive amount of starch are 50g/L；

(3) in treatment with supercritical fluid system, temperature in autoclave is risen to 100 by high/low temperature all-in-one machine DEG C, it is gelatinized 25 minutes under 190 revs/min of magnetic stirrers, obtains starch gel compound；

(4) in treatment with supercritical fluid system, it is continually fed into CO₂1 hour starch gel compound into step (3), Gas flow rate is 80 ml/mins, and decompression makes the starch gel compound in step (3) be cooled to room temperature (25 DEG C)/normal pressure later Starch-based foam is made in (standard atmospheric pressure)；

Thermoplasticity made from the impact of performance and embodiment 1 of thermoplastic starch-based composite material made from embodiment 16-20 The impact of performance of starch-based composite material is suitable.

Comparative example 1

The formula rate of following table 4 prepares thermoplastic starch-based composite material.

(1) by starch (tapioca), plasticiser (glycerol) and preplasticizing dispersing agent (water) 5:2:3 in mass ratio in machinery It is cut dispersion mixing 1 hour in blender, starch mixed liquor is made, the additive amount of starch is 50g/L；

(2) by step (1) mix starch mixed liquor is put into reaction kettle, be warming up to 85 DEG C under normal pressure, 190 turns/ It is gelatinized 20 minutes under minute magnetic stirrer, obtains starch gel compound, wherein the inventory of starch mixed liquor is 100g/L；

(3) step (2) are made after thermoplastic starch is put into 80 DEG C of infrared ray direct heat drying casees dryings 8 hours and are put into 80 DEG C Vacuum oven is 8 hours dry, moisture content≤0.5wt% of starch resin after control is dry.

Comparative example 2

(1) by starch (tapioca), plasticiser (glycerol) and preplasticizing dispersing agent (water) 5:2:3 in mass ratio in machinery It is cut dispersion mixing 1 hour in blender, and nano-cellulose 0.02PHR is added, starch mixed liquor is made, wherein nanofiber The specific surface area of element is 120m²/ g, diameter 20nm, the additive amount of starch are 50g/L；

Comparative example 3

(1) by starch (tapioca), plasticiser (glycerol) and preplasticizing dispersing agent (water) 5:2:3 in mass ratio in machinery It is cut dispersion mixing 1 hour in blender, and nano-cellulose 0.02PHR and glutaraldehyde 0-3.2PHR is added, it is mixed that starch is made Liquid is closed, wherein glutaraldehyde exists in form of an aqueous solutions as hydrophobic anti-agent, mass fraction 25%, the ratio table of nano-cellulose Area is 120m²/ g, diameter 20nm, the additive amount of starch are 50g/L；

Comparative example 4

In addition to the additive amount of glutaraldehyde water solution is different, other conditions are the same as comparative example 3.

Comparative example 5

Comparative example 6

Comparative example 7

Comparative example 8

Formula rate described in following table 5 prepares thermoplastic starch based foam material.

(1) by starch (tapioca), plasticiser (glycerol) and preplasticizing dispersing agent (water) 5:2:3 in mass ratio are in machinery It is cut dispersion mixing 1 hour in blender, starch mixed liquor is made, the additive amount of starch is 50g/L；

(4) in treatment with supercritical fluid system, it is continually fed into CO₂2 hours starch gel compounds into step (3) In, gas flow rate be 80 ml/mins, later decompression make the starch gel compound in step (3) be cooled to room temperature (25 DEG C)/often It presses (standard atmospheric pressure), starch-based foam is made；

Comparative example 9

(1) by starch (tapioca), plasticiser (glycerol) and preplasticizing dispersing agent (water) 5:2:3 in mass ratio are in machinery It is cut dispersion mixing 1 hour in blender, and nano-cellulose 0.02PHR is added, starch mixed liquor is made, wherein nanofiber The specific surface area of element is 120m²/ g, diameter 20nm, the additive amount of starch are 50g/L；

Comparative example 10

Other than removing carbon dioxide pressure is different, other conditions are the same as comparative example 8.

Comparative example 11

Other than removing carbon dioxide pressure is different, other conditions are the same as comparative example 9.

Comparative example 12

Comparative example 13

Comparative example 14

(1) by starch (tapioca), plasticiser (glycerol) and preplasticizing dispersing agent (water) 5:2:3 in mass ratio are in machinery It is cut dispersion mixing 1 hour in blender, starch mixed liquor is made, the additive amount of starch is 30g/L；

(2) by above-mentioned (1) item mix starch mixed liquor is put into autoclave, at 25 DEG C with booster pump pressurization two Carbonoxide is to 7.0MPa, and wherein the inventory of starch mixed liquor is 70g/L；

Comparative example 15

(1) by starch (tapioca), plasticiser (glycerol) and preplasticizing dispersing agent (water) 5:2:3 in mass ratio are in machinery It is cut dispersion mixing 1 hour in blender, and nano-cellulose 0.02PHR is added, starch mixed liquor is made, wherein nanofiber The specific surface area of element is 120m²/ g, diameter 20nm, the additive amount of starch are 60g/L；

(2) by above-mentioned (1) item mix starch mixed liquor is put into autoclave, at 25 DEG C with booster pump pressurization two Carbonoxide is to 7.0MPa, and wherein the inventory of starch mixed liquor is 140g/L；

The formula rate (mass fraction) of 1 embodiment 1-5 of table

The formula rate (mass fraction) of 2 embodiment 6-10 of table

The formula rate (mass fraction) of 3 embodiment 11-15 of table

The formula rate (mass fraction) of 4 comparative example 1-7 of table

The formula rate (mass fraction) of 5 comparative example 8-13 of table

Through performance test, foam performance parameter obtained by embodiment 1-15, comparative example 1-13 is shown in Table 6-10 and Fig. 1-8.

The performance parameter of the foamed material of 6 embodiment 1-5 of table

As shown in Table 6, expansion ratio, the cell density of foamed material obtained by embodiment 2 are apparently higher than other implementations Example, and foamed material obtained by embodiment 2 is placed 56 days under 20 DEG C/50% relative humidities after moisture content be lower than its His embodiment.

The performance parameter of the foamed material of 7 embodiment 6-10 of table

As shown in Table 7, expansion ratio, the cell density of foamed material obtained by embodiment 8 are apparently higher than other implementations Example, and foamed material obtained by embodiment 8 is placed 56 days under 20 DEG C/50% relative humidities after moisture content be lower than its His embodiment.

The performance parameter of the foamed material of 8 embodiment 11-15 of table

As shown in Table 8, expansion ratio, the cell density of foamed material obtained by embodiment 14 are apparently higher than other implementations Example, and foamed material obtained by embodiment 14 placed 56 days under 20 DEG C/50% relative humidities after moisture content be lower than Other embodiments.

The performance parameter of the material of 9 comparative example 1-7 of table

The performance parameter of the foamed material of 10 comparative example 8-13 of table

As shown in Table 10, comparative example 8-13 does not add resistance to water reaction agent, compared under the same terms in long-term placement process The foamed material of preparation, moisture content rise, and water resistance is deteriorated.Using foamed material obtained by comparative example 12 and 13 of the present invention Expansion ratio, cell density are apparently higher than its comparative example 8,9,10 and 11, and foamed material obtained by comparative example 12 and 13 exists Moisture content after placing 56 days under 20 DEG C/50% relative humidities is lower than other comparative examples.But due to comparative example 12,13 In, it is not added with resistance to water reaction agent, expansion ratio has added the embodiment 11-15 of resistance to water reaction agent to send out compared with (pressure) under the same terms Steep that multiplying power is low, poor water resistance.

Fig. 1 is embodiment 1-15, and the thermoplastic starch based foam material density and expansion ratio of comparative example 1-13 is with penta 2 Aldehyde aqueous solution additive amount change curve.Wherein, ● it is comparative example 1,For comparative example 2,For comparative example 3,For comparative example 4, For comparative example 5,It is comparative example 7 for comparative example 6, zero, ■ is comparative example 8,For comparative example 9, ▲ it is comparative example 10, ▼ is comparison Example 11, △ are comparative example 12, and ▽ is comparative example 13,For embodiment 1,For embodiment 2,For embodiment 3,For embodiment 4, For embodiment 5,For embodiment 6,For embodiment 7,For embodiment 8,For embodiment 9, ★ is embodiment 10,For embodiment 11,For embodiment 12, ◇ is embodiment 13, and is embodiment 14, and ☆ is embodiment 15.As shown in Figure 1, without overcritical two It is 1.5g/cm that the comparative example 1-7 of carbonoxide secondary process, which gradually increases its density with the additive amount of glutaraldehyde,³Left and right is kept not Become, and with the additive amount of glutaraldehyde to gradually increase its density significant by the embodiment 1-15 after supercritical carbon dioxide secondary process It reduces, and the minimum 0.03g/cm of 20 density of embodiment³, expansion ratio is up to 50.

Fig. 2 is the abscess-size and cell density of the thermoplastic starch based foam material of embodiment 1-15 and comparative example 8-13 With glutaraldehyde water solution additive amount change curve.Wherein, ■ is comparative example 8,For comparative example 9, ▲ it is comparative example 10, ▼ is Comparative example 11, △ are comparative example 12, and ▽ is comparative example 13,For embodiment 1,For embodiment 2,For embodiment 3,To implement Example 4,For embodiment 5,For embodiment 6,For embodiment 7,For embodiment 8,For embodiment 9, ★ is embodiment 10,For Embodiment 11,For embodiment 12, ◇ is embodiment 13, and is embodiment 14, and ☆ is embodiment 15.As shown in Figure 2, face with super The pressure of boundary's carbon dioxide gradually increases, and the abscess-size of comparative example 8,10 and 12 is gradually reduced, and cell density gradually increases, and It is modified through glutaraldehyde, the significant reduction of the abscess-size of embodiment and the significant increase of cell density, wherein 14 abscess ruler of embodiment Very little minimum, cell density are maximum.

Fig. 4 is the cross-section morphology SEM photograph of the thermoplastic starch based foam material of embodiment 2-4,7-9,12-14.Wherein, (h) it is embodiment 2, (i) is embodiment 3, (j) be embodiment 4, (m) be embodiment 7, (n) be embodiment 8, (o) is embodiment 9, (r) it is embodiment 12, (s) is embodiment 13, (t) is embodiment 14.It is shown on the cross-section morphology of embodiment as shown in Figure 4 High uniformity and foam structure interconnected, and do not occur foam structure in comparative example.

Fig. 5 is embodiment 1-15, and the melt index of the thermoplastic starch based foam material of comparative example 1-13 is with glutaraldehyde water Solution additive amount change curve.Wherein, ● it is comparative example 1,For comparative example 2,For comparative example 3,For comparative example 4,It is right Ratio 5,It is comparative example 7 for comparative example 6, zero, ■ is comparative example 8,For comparative example 9, ▲ it is comparative example 10, ▼ is comparative example 11, △ be comparative example 12, and ▽ is comparative example 13,For embodiment 1,For embodiment 2,For embodiment 3,For embodiment 4,For Embodiment 5,For embodiment 6,For embodiment 7,For embodiment 8,For embodiment 9, ★ is embodiment 10,For embodiment 11,For embodiment 12, ◇ is embodiment 13, and is embodiment 14, and ☆ is embodiment 15.As shown in Figure 5, without overcritical The comparative example 1-7 of carbon dioxide secondary process gradually increases its melt index with glutaraldehyde additive amount and is decreased obviously, and passes through super The embodiment 1-15 of critical carbon dioxide secondary process with glutaraldehyde additive amount gradually increase its melt index decline it is slower, together When, comparative example 8,10 and 12 melt index are higher than comparative example 1.

Fig. 6 is embodiment 1-15, and the thermoplastic starch based foam material of comparative example 1-13 is in 20 DEG C/50% relative humidity item Under part moisture content with standing time change curve.Wherein, ● it is comparative example 1,For comparative example 2,For comparative example 3,For Comparative example 4,For comparative example 5,It is comparative example 7 for comparative example 6, zero, ■ is comparative example 8,For comparative example 9, ▲ it is comparative example 10, ▼ be comparative example 11, and △ is comparative example 12, and ▽ is comparative example 13,For embodiment 1,For embodiment 2,For embodiment 3, For embodiment 4,For embodiment 5,For embodiment 6,For embodiment 7,For embodiment 8,For embodiment 9, ★ is embodiment 10,For embodiment 11,For embodiment 12, ◇ is embodiment 13, and is embodiment 14, and ☆ is embodiment 15.It will be appreciated from fig. 6 that It is not added with the modified comparative example 1 of glutaraldehyde and 2 long-time moisture content of comparative example retains numerical value and is apparently higher than comparative example 8-13 respectively, And the aqueous rate score of its long-time of embodiment 1-15 through supercritical carbon dioxide secondary process is significantly lower than comparative example 1-7.It puts After setting 56 days, the aqueous rate score of embodiment 14 is significantly lower than comparative example 1 and comparative example 8.

Fig. 7 is the thermoplastic starch based foam material of embodiment 1-15 and comparative example 8-13 in 20 DEG C/50% relative humidity Under the conditions of initial incompressible intensity with glutaraldehyde water solution additive amount change curve.It wherein, is comparative example 8,For comparative example 9, ▲ it is comparative example 10, ▼ is comparative example 11, and △ is comparative example 12, and ▽ is comparative example 13,For embodiment 1,For embodiment 2,For embodiment 3,For embodiment 4,For embodiment 5,For embodiment 6,For embodiment 7,For embodiment 8,For embodiment 9, ★ be embodiment 10,For embodiment 11,For embodiment 12,For embodiment 13, is embodiment 14, and ☆ is embodiment 15.As shown in Figure 7, it is not added with the modified comparative example 1 of glutaraldehyde and the initial incompressible intensity of comparative example 2 is apparently higher than comparison respectively Example 8-13, and its incompressible intensity of the embodiment 1-15 through supercritical carbon dioxide secondary process is lower than comparative example 1-7.

Fig. 8 is the thermoplastic starch based foam material of embodiment 1-15 and comparative example 8-13 in 20 DEG C/50% relative humidity Under the conditions of incompressible intensity with standing time change curve.Wherein, ■ is comparative example 8,For comparative example 9, ▲ it is comparative example 10, ▼ be comparative example 11, and △ is comparative example 12, and ▽ is comparative example 13,For embodiment 1,For embodiment 2,For embodiment 3, For embodiment 4,For embodiment 5,For embodiment 6,For embodiment 7,For embodiment 8,For embodiment 9, ★ is embodiment 10,For embodiment 11,For embodiment 12, ◇ is embodiment 13, and is embodiment 14, and ☆ is embodiment 15.As shown in Figure 8, Being not added with the modified comparative example 1 of glutaraldehyde and comparative example 2, incompressible strength values are apparently higher than comparative example 8-13 respectively for a long time, And the incompressible strength values of its long-time of embodiment 1-15 through supercritical carbon dioxide secondary process are significantly lower than comparative example 1- 7, but the incompressible strength retention ratio of embodiment 1-15 is apparently higher than comparative example 1-7 in placement process.After placing 56 days, embodiment 14 incompressible strength values are almost as comparative example 1 and comparative example 8.

Claims

1. a kind of preparation method of thermoplastic starch based foam material comprising following step:

(1) in mass ratio it is 1:(0.2-0.4 by starch, plasticiser and preplasticizing dispersing agent): (0.2-1.2) is uniformly mixed, and is obtained Starch mixed liquor I；The additive amount of the starch is 40-50g/L, and the additive amount of above-mentioned starch is the quality and step of the starch (3) in treatment with supercritical fluid system reaction kettle volume the ratio between；

(3) in treatment with supercritical fluid system, it is solidifying that starch is made in starch mixed liquor I I hybrid reaction described in step (2) Gelatinizer；Wherein, the temperature of the hybrid reaction is 70-120 DEG C, and the time of the hybrid reaction is 10-40 minutes；The shallow lake The inventory of powder mixed liquor I I is less than 130g/L, the quality and the shooting flow that above-mentioned inventory is the starch mixed liquor I I In body processing system reaction kettle volume the ratio between；

(4) in treatment with supercritical fluid system, supercritical fluid is continually fed into the starch gel compound, is subtracted later Pressure, cooling are to get thermoplastic starch based foam material.

2. the preparation method of thermoplastic starch based foam material as described in claim 1, which is characterized in that in step (1), institute The starch that the starch stated is selected from native starch and/or is modified by starch dressing agent；The native starch is better selected from corn One of starch, wheaten starch, starch from sweet potato, potato starch and tapioca are a variety of, are more preferably tapioca；Institute The starch dressing agent stated is better selected from one of carboxylic acid, acid anhydrides, carboxylic acid halides and amide or a variety of；Wherein, the carboxylic acid compared with It goodly is one of citric acid, acetic acid, malic acid and sebacic acid or a variety of；The acid anhydrides be preferably acetic anhydride and/or Maleic anhydride；The carboxylic acid halides is preferably acyl chlorides；The amide is preferably formamide, N-METHYLFORMAMIDE and dimethyl One of acetamide is a variety of；

And/or in step (1), described be mixed into machine mixer cuts dispersion mixing, preferably in machine mixer Middle cutting dispersion mixing 0.5-1 hours；

And/or in step (1), the plasticiser is one of ethylene glycol, glycerine, dimethyl sulfoxide and urea or more Kind；

And/or in step (1), the preplasticizing dispersing agent is one of ethyl alcohol, water and methanol or a variety of；

And/or in step (1), in starch mixed liquor I, the matter of the starch, the plasticiser and the preplasticizing dispersing agent Amount is than being 1:(0.2-0.4): (0.6-1), preferably 1:(0.2-0.4): (0.6-0.8).

3. the preparation method of thermoplastic starch based foam material as described in claim 1, which is characterized in that in step (2), institute It states resistance to water reaction agent and is selected from one of more aldehydes, amides, polyvinyl alcohol and organic acid anhydride or a variety of, it is preferably more Aldehydes；The amides are preferably formamide；

And/or in step (2), the resistance to water reaction agent exists in form of an aqueous solutions, in the aqueous solution of resistance to water reaction agent, The mass percent of resistance to water reaction agent is preferably 20-40%, is more preferably 25%；

And/or in step (2), the reinforcing agent is plant fiber, nano-cellulose, bacteria cellulose, polylactic acid, chitosan With one of polyesteramide or a variety of, preferably one of plant fiber, nano-cellulose and bacteria cellulose or more Kind, it is more preferably nano-cellulose；

And/or in step (2), the specific surface area of the reinforcing agent is 100-150m²/ g, preferably 120m²/g；The enhancing The diameter of agent is 10-30nm, preferably 20nm.

4. the preparation method of thermoplastic starch based foam material as claimed in claim 3, which is characterized in that when described water-fast anti- When to answer agent be more aldehydes, the mass ratio of the resistance to water reaction agent and the starch is (0-3.2): 100, preferably (0.2-1.6): 100, be more preferably (0.4-1.6): 100, such as (0.8-1.6): 100；

When the resistance to water reaction agent is no esters, the mass ratio of the resistance to water reaction agent and the starch is (0-32): 100；

When the resistance to water reaction agent is amides, the mass ratio of the resistance to water reaction agent and the starch is (0-5): 100, preferably (1.25-5): 100, such as 1.6:100；

When the resistance to water reaction agent is polyvinyl alcohol, the mass ratio of the resistance to water reaction agent and the starch is (0- 10): 100, preferably (1.6-2.5): 100, such as 2:100；

When the resistance to water reaction agent is organic acid anhydride, the mass ratio of the resistance to water reaction agent and the starch is (0-3):100；

And/or more aldehydes are one of glyoxal, butanedial and glutaraldehyde or a variety of；

And/or the amides are formamide and/or acetamide；

And/or the organic acid anhydride is one of citric acid, succinic acid, maleic anhydride and ortho-xylene acid anhydrides or more Kind.

5. the preparation method of thermoplastic starch based foam material as claimed in claim 3, which is characterized in that when reinforcing agent is to plant When fibres element, the mass ratio of the reinforcing agent and the starch is (0.01-0.04): 100, preferably 0.02:100；

When reinforcing agent is nano-cellulose, the mass ratio of the reinforcing agent and the starch is (0.01-0.04): 100, preferably Ground is 0.02:100；

When reinforcing agent is bacteria cellulose, the mass ratio of the reinforcing agent and the starch is (0.01-0.08): 100；

When reinforcing agent is chitosan, the mass ratio of the reinforcing agent and the starch is 0.1:100.

6. the preparation method of thermoplastic starch based foam material as described in claim 1, which is characterized in that in step (3), use The substance for making supercritical fluid is CO₂、H₂O、CH₄、CH₃OH、C₂H₅OH or NH₃；

And/or in step (3), the hybrid reaction carries out in a high pressure reaction kettle；The temperature of the hybrid reaction is 70-100℃；The time of the hybrid reaction is 15-25 minutes；

And/or in step (3), starch mixed liquor I I described in step (2) is placed in the treatment with supercritical fluid system Operation carry out in the steps below: starch mixed liquor I I described in step (2) is placed in autoclave, at 15-25 DEG C It is lower to be pressurized supercritical fluid to 7-25MPa with booster pump；

And/or in step (3), when the hybrid reaction, stirring rate is 100-300 revs/min；

And/or in step (3), the inventory of the starch mixed liquor I I is 80g/L-130g/L；

Described when being continually fed into the supercritical fluid and/or in step (4), gas flow rate is 50-150 ml/min；It is logical Entering the supercritical fluid time is 1-3 hours.

7. the preparation method of thermoplastic starch based foam material as claimed in claim 6, which is characterized in that in step (3), use The substance for making supercritical fluid is CO₂；

And/or in step (3), the temperature of the hybrid reaction is 85 DEG C；The time of the hybrid reaction is 20 points Clock；

And/or the pressure in the autoclave is 7-20MPa, such as 9MPa or 11MPa；

And/or in step (3), when the hybrid reaction, stirring rate is 190 revs/min；

And/or in step (3), the inventory of the starch mixed liquor I I is 100g/L；

Described when being continually fed into the supercritical fluid and/or in step (4), gas flow rate is 80 ml/mins；It is passed through super The critical fluids time is 2 hours.

8. the preparation method of thermoplastic starch based foam material as described in claim 1, which is characterized in that by step (4) institute The thermoplastic starch based foam material stated removes the preformed agent in step (1)；The preformed agent removed in step (1) Preferably the starch gel compound is dried for operation.

9. the preparation method of thermoplastic starch based foam material as claimed in claim 8, which is characterized in that the temperature of the drying Degree is 0-100 DEG C, preferably 60-100 DEG C；

And/or the time of the drying is 0.5-50 hours, preferably 2-50 hours；

And/or the operation of the drying carries out in the steps below: by the starch gel compound be first placed in air dry oven or After infrared ray direct heat drying case is dry, places into vacuum oven or dew point drying box is dry；The moisture content control of product after drying System is in≤0.5wt%；

Wherein, the air dry oven or the temperature of infrared ray direct heat drying case drying are preferably 75-85 DEG C, are more preferably 80 ℃；Dry time preferably 5-10 hours of the air dry oven or infrared ray direct heat drying case, are more preferably 8 hours；Institute The temperature for stating vacuum oven or the drying of dew point drying box is preferably 0-100 DEG C, is more preferably 60-100 DEG C, is most preferably 80 ℃；The time of the vacuum oven or the drying of dew point drying box is preferably 4-30 hours, is more preferably 10-30 hours, most It goodly is 8 hours.

10. a kind of thermoplastic starch based foam material as made from claim 1-9 described in any item preparation methods.